The writing process for the majority of Metallicaâs albums have followed the same process. A large slew of guitar riffs written primarily by James Hetfield, sometimes Kirk Hammett, and rarely the bandâs bass player, (that now being bass virtuoso Robert Trujillo) are reviewed and selected.
1 Delhi is most polluted city in the world in PM2.5 concentrations. 2  Half of the top 20 most polluted cities were in India, according to data.  PM2.5 is considered most harmful to health.
But India, Pakistan and Iran are also home to some of the world's most polluted cities in terms of particulate matter, according to the most recent statistics from the WHO, compiled from more than 1,600 cities for the years 2008 to 2013. The WHO examined the concentration of fine particles suspended in the atmosphere.